.nav {
    height: 40px;
    width: 100%;
    /* background-color: #fcfcfc; */
    border-top: 3px solid #a6c0fe;
    border-bottom: 1px solid #dde1e9;
    line-height: 40px;
    *background: #95a8d418; 
}

.nav a {
    float: left;
    width: 25%;
    height: 40px;
    font-size: 17px;
    font-weight: bold;
    letter-spacing: 3px;
    color: #7988adbe;
    text-align:center;
    text-decoration: none;
}
.nav a:hover {
    border-radius:30px;
    background: #d2d9eb;
    color: #4c5f8fda;
    text-decoration: underline;
}
.content_1{
	width:100%;
	height:200px;
	font-size:50px;
	text-align:center;
	line-height: 200px;
	color:chartreuse;
}

.content_2{
	width:100%;
	height:200px;
	font-size:50px;
	text-align:center;
	line-height: 200px;
	color:orangered;
}

.nav #index{
    width: 30%;
}
.nav #index2{
    width: 30%;
}
.nav #index3{
    width: 30%;
}
.nav #login{
    width: 10%;
}